A typical septic system includes septic/aerobic tank or a septic/aerobic tank and pump tank where primary treatment of wastewater takes place. The effluent wastewater then flows to a disposal area, buried in the soil, for secondary treatment and disposal into the ground. In conventional septic systems, the disposal area can include a disposal bed or trenches with stone and pipe laterals, or a disposal bed or trenches with infiltration chambers, or seepage pits. Secondary treatment of wastewater will typically naturally occur at the interface between the disposal area and the soil adjacent to or below the disposal area. This soil may be imported sand, native soil, or other locally permitted permeable material, and the interface between the disposal area and the soil is where the secondary treatment process of the wastewater takes place becomes a biological mat (bio-mat). The bio-mat should be typically be maintained in an aerobic state for long term operation of a wastewater disposal system to occur. Where aerobic conditions are not typically maintained, the bio-mat will thicken much more quickly and failure of the disposal area will result quicker than a typical aerobic state disposal bed.
In normally functioning septic disposal areas, the wastewater is naturally and microbiologically processed as it passes through the bio-mat and subsurface fill material (or native soil) by aerobic and anaerobic bacteria and micro-organisms (bugs). The top few inches of sand or soil develop into a bio-mat which bugs and other bacteria which helps digest the wastewater. These bugs will be both combination of aerobic and anaerobic organisms. The effluent of a septic tank contains substantial anaerobic bacteria, and unless the disposal area is maintained in an aerobic state, the anaerobic bugs will flourish and the bio-mat will tend to thicken and the disposal area will clog prematurely with anaerobic sludge.
Adequate air is typically available to supply aerobic bacteria with oxygen at the bio-mat interface of the secondary treatment area, since a typical disposal area is shallow and covered with grass which is a pervious material. If the disposal area is affected by site specific conditions which do not allow for a shallow disposal bed covered with grass, anaerobic condition can occur. For example, the site specific conditions may include, but are not limited to, the disposal area is too deep in the ground, or underneath parking areas which prevent adequate oxygen from reaching the disposal bed; and/or the disposal area is influenced by leaky plumbing fixtures and/or by surface or subsurface groundwater conditions that hydraulically overload the disposal bed beyond the hydraulic conductivity of the bio-mat.
The bio-mat for a septic system will typically remain adequately permeable for 10-40 years. In cases where disposal areas are adversely affected by one of the above, anaerobic conditions can occur in the disposal area and resultant premature failure of the disposal area can occur in less than 10 years.
It is known that the biochemical processing of wastewater is enhanced by flowing air or other active gas through secondary wastewater treatment processes, and the temperature of the aerobic environment will affect the aerobic activity rate. Typically, the air flows to or from auxiliary pipes in the soil run parallel to and spaced apart from perforated lateral pipes so that the air can flow to or from the wastewater distribution laterals. The auxiliary pipes are either evacuated or pressurized relative to induce aeration of the surrounding area. Disposal areas aeration technology can be applied to new installations or retrofitted onto old installations. The subject invention improves this known process, specific to onsite wastewater disposal, by allowing multiuse lateral installations under and within the zone of treatment of a secondary treatment area following a septic tank to provide rejuvenating properties and continuous/intermittent long term aeration through the multiuse permanent installation laterals for air/fluid airwashing, backwashing, and long term aeration maintenance. The subject invention results in the ability to maintain a secondary treatment/disposal area indefinitely by allowing cleaning out of treatment/disposal areas by locally licensed waste haulers, therefore minimizing environmental impacts of mining activities, and minimizing hazardous disposal volumes at local landfills for contaminated soil typically removed from septic disposal systems. Licensed waste haulers typically deliver the liquids and solids to local wastewater treatment facilities for tertiary treatment and ultimate disposal per state and local requirements.
Proper disposal area performance can be affected if the soil layer is thicker or less permeable over the leaching system. This will lead to a rise of anaerobic bacteria in the bio-mat and a potential environmental hazard when the disposal area fails and surfacing of effluent on the ground, or backup of plumbing occurs.
In some disposal area installations, the soil is topped by a bituminous pavement or analogous material which is vastly different from soil, and which pavement has either limited permeability or uneven permeability, due to changes thickness, density, cracks, and so forth.
Thus, there is a need to provide a system to be able to maintain aerobic conditions in the disposal area and the bio-mat, specifically where the system properly aerates the bio-mat. Typically, previous aeration technology involves aeration of the disposal area by pressurization of the disposal area from above the bio-mat, this technology does not significantly improve the aerobic condition of the soil beneath the bio-mat where aerobic bacteria need to survive for long term operation of the disposal area. The present invention results in aerobic conditions beneath thin aerobic conditions where previous technology does not. The aerobic conditions are variably maintained by controlling the amount of air and hence, oxygen flow is regulated with automatic or manual on off operation of the blower. The blower aerates the soil bio-mat interface from below and as the air rises to the atmosphere, the oxygen in the air allows aerobic bacteria to thrive on either side of the bio-mat for sewage disposal systems.